Previous research has found that mindfulness meditation can reduce stress and anxiety in the general population as well as in breast cancer survivors. But, there hadn't been many large, clinical trials to test the value of the practice among breast cancer patients, said study author Cecile Lengacher, director of the predoctoral fellowship program at the University of South Florida, in Tampa.

In her study, those who took part in the six-week program had less anxiety, fear of recurrence and less fatigue compared to those who did not take the program, she found. The effect was small to moderate, she added.

"It works right away," Lengacher said of the program, known as Mindfulness-Based Stress Reduction.

The results also seemed to last through 12 weeks of follow-up. "Even after they completed the program, the benefits continued through the 12 weeks," she said. "It is a program that once you learn it, you have it for life."

For the study, Lengacher and her colleagues randomly assigned 322 women who had been treated for breast cancer to the six-week mindfulness program or to a comparison group that did not learn the technique. At the study's start, and again at six and 12 weeks, the researchers assessed the participants' symptoms. In all, 299 women completed the study. The instruction helped reduce fear of recurrence and fatigue the most, the study found. The effect was small to moderate, Lengacher added.

At the core of the program are four techniques. They include: meditation with a focus on breathing, yoga, a body scan technique (where participants learn to become aware of the entire body) and walking meditation.

The instruction trains people to be aware and pay attention to the present. "We teach them to attend to the breath and to bodily sensations," Lengacher said. Through the practice, "by this constant attention and concentration, the person learns to self-regulate their emotions."

Being in the present, she said, "reduces the amount of worrying about the past, worrying about the future."

The study findings rang true with Susan Castledine, 71, of Los Angeles, who was diagnosed with breast cancer two and a half years ago.

"I did tai chi all the way through, which I consider a form of meditation," said the former school administrator and journalism instructor.

More recently, Castledine completed an online mindfulness program. "Not only did they talk about mindfulness and how they used it in their lives, they would do meditation with you," she said of the program leaders.

These days, she tries to meditate every night, "anywhere from 2 to 15 minutes," she said. Castledine also incorporates the mindfulness techniques into daily activities.

She said she finds it stress-relieving. "If I had been doing meditation at the time [of her treatment], I think it would have relieved my stress," she added.

One cancer care expert was more cautious in interpreting the study findings.

The effects of the meditation "were meaningful, but they were moderate," said Matthew Loscalzo, the Liliane Elkins Professor in Supportive Care Programs at the City of Hope Cancer Center, in Duarte, Calif.

"They were largest for the fear of recurrence problems," he said.

One limitation of the study, he said, was that the follow-up was relatively brief, just 12 weeks. It's also not possible to know whether the improvements in stress and other areas were completely due to the meditation, or also to the social support provided by the group.

Experts do know, Loscalzo said, that mindfulness meditation "can be helpful for anxiety and stress." Less research has been done in cancer patients, he added.

The study was published online May 31 in the Journal of Clinical Oncology.